A long, thin, sterile wire intended to be percutaneously placed into the cardiac vasculature (ventricles or coronary vessels) to function as a guide for the introduction, positioning, and/or operation of a device (e.g., catheter, pacing lead); it may also be used in the peripheral vasculature. It may be made of metal (e.g., stainless steel, Nitinol), or polymer and/or glass materials to provide MRI-compatibility, with or without coating, and is available in a variety of distal tip designs. It is used for various diagnostic and interventional procedures, and may include devices used to facilitate manipulation (e.g., torque device). This is a single-use device.